/*
 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
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/*
 * Licensed Materials - Property of IBM
 * RMI-IIOP v1.0
 * Copyright IBM Corp. 1998 1999  All Rights Reserved
 *
 */

package com.sun.corba.se.impl.javax.rmi.CORBA; // Util (sed marker, don't remove!)

import java.rmi.RemoteException;
import java.rmi.UnexpectedException;
import java.rmi.MarshalException;

import java.rmi.server.RMIClassLoader;

import java.util.Hashtable;
import java.util.Enumeration;
import java.util.Properties;
import java.util.Map;
import java.util.WeakHashMap;

import java.io.Serializable;
import java.io.NotSerializableException;

import java.lang.reflect.Constructor;

import javax.rmi.CORBA.ValueHandler;
import javax.rmi.CORBA.Tie;

import java.security.AccessController;
import java.security.PrivilegedAction;

import java.rmi.MarshalException;
import java.rmi.NoSuchObjectException;
import java.rmi.AccessException;
import java.rmi.Remote;
import java.rmi.ServerError;
import java.rmi.ServerException;
import java.rmi.ServerRuntimeException;

import javax.transaction.TransactionRequiredException;
import javax.transaction.TransactionRolledbackException;
import javax.transaction.InvalidTransactionException;

import org.omg.CORBA.SystemException;
import org.omg.CORBA.Any;
import org.omg.CORBA.TypeCode;
import org.omg.CORBA.COMM_FAILURE;
import org.omg.CORBA.BAD_PARAM;
import org.omg.CORBA.INV_OBJREF;
import org.omg.CORBA.NO_PERMISSION;
import org.omg.CORBA.MARSHAL;
import org.omg.CORBA.OBJECT_NOT_EXIST;
import org.omg.CORBA.TRANSACTION_REQUIRED;
import org.omg.CORBA.TRANSACTION_ROLLEDBACK;
import org.omg.CORBA.INVALID_TRANSACTION;
import org.omg.CORBA.BAD_OPERATION;
import org.omg.CORBA.ACTIVITY_REQUIRED;
import org.omg.CORBA.ACTIVITY_COMPLETED;
import org.omg.CORBA.INVALID_ACTIVITY;
import org.omg.CORBA.CompletionStatus;
import org.omg.CORBA.TCKind;
import org.omg.CORBA.portable.UnknownException;
import org.omg.CORBA.portable.InputStream;
import org.omg.CORBA.portable.OutputStream;

// This class must be able to function with non-Sun ORBs.
// This means that any of the following com.sun.corba classes
// must only occur in contexts that also handle the non-Sun case.

import com.sun.corba.se.pept.transport.ContactInfoList;
import com.sun.corba.se.spi.orb.ORB;
import com.sun.corba.se.spi.orb.ORBVersionFactory;
import com.sun.corba.se.spi.protocol.CorbaClientDelegate;
import com.sun.corba.se.spi.transport.CorbaContactInfoList;
import com.sun.corba.se.spi.protocol.LocalClientRequestDispatcher;
import com.sun.corba.se.spi.copyobject.ReflectiveCopyException;
import com.sun.corba.se.spi.copyobject.CopierManager;
import com.sun.corba.se.spi.copyobject.ObjectCopierFactory;
import com.sun.corba.se.spi.copyobject.ObjectCopier;
import com.sun.corba.se.impl.io.ValueHandlerImpl;
import com.sun.corba.se.impl.orbutil.ORBConstants;
import com.sun.corba.se.impl.orbutil.ORBUtility;
import com.sun.corba.se.impl.logging.OMGSystemException;
import com.sun.corba.se.impl.util.Utility;
import com.sun.corba.se.impl.util.IdentityHashtable;
import com.sun.corba.se.impl.util.JDKBridge;
import com.sun.corba.se.impl.logging.UtilSystemException;
import com.sun.corba.se.spi.logging.CORBALogDomains;
import sun.corba.SharedSecrets;

/**
 * Provides utility methods that can be used by stubs and ties to
 * perform common operations.
 */
public class Util implements javax.rmi.CORBA.UtilDelegate {

  // Runs as long as there are exportedServants
  private static KeepAlive keepAlive = null;

  // Maps targets to ties.
  private static IdentityHashtable exportedServants = new IdentityHashtable();

  private static final ValueHandlerImpl valueHandlerSingleton =
      SharedSecrets.getJavaCorbaAccess().newValueHandlerImpl();

  private UtilSystemException utilWrapper = UtilSystemException.get(
      CORBALogDomains.RPC_ENCODING);

  private static Util instance = null;

  public Util() {
    setInstance(this);
  }

  private static void setInstance(Util util) {
    assert instance == null : "Instance already defined";
    instance = util;
  }

  public static Util getInstance() {
    return instance;
  }

  public static boolean isInstanceDefined() {
    return instance != null;
  }

  // Used by TOAFactory.shutdown to unexport all targets for this
  // particular ORB.  This happens during ORB shutdown.
  public void unregisterTargetsForORB(org.omg.CORBA.ORB orb) {
    for (Enumeration e = exportedServants.keys(); e.hasMoreElements(); ) {
      java.lang.Object key = e.nextElement();
      Remote target = (Remote) (key instanceof Tie ? ((Tie) key).getTarget() : key);

      // Bug 4476347: BAD_OPERATION is thrown if the ties delegate isn't set.
      // We can ignore this because it means the tie is not connected to an ORB.
      try {
        if (orb == getTie(target).orb()) {
          try {
            unexportObject(target);
          } catch (java.rmi.NoSuchObjectException ex) {
            // We neglect this exception if at all if it is
            // raised. It is not harmful.
          }
        }
      } catch (BAD_OPERATION bad) {
                /* Ignore */
      }
    }
  }

  /**
   * Maps a SystemException to a RemoteException.
   *
   * @param ex the SystemException to map.
   * @return the mapped exception.
   */
  public RemoteException mapSystemException(SystemException ex) {
    if (ex instanceof UnknownException) {
      Throwable orig = ((UnknownException) ex).originalEx;
      if (orig instanceof Error) {
        return new ServerError("Error occurred in server thread", (Error) orig);
      } else if (orig instanceof RemoteException) {
        return new ServerException("RemoteException occurred in server thread",
            (Exception) orig);
      } else if (orig instanceof RuntimeException) {
        throw (RuntimeException) orig;
      }
    }

    // Build the message string...
    String name = ex.getClass().getName();
    String corbaName = name.substring(name.lastIndexOf('.') + 1);
    String status;
    switch (ex.completed.value()) {
      case CompletionStatus._COMPLETED_YES:
        status = "Yes";
        break;
      case CompletionStatus._COMPLETED_NO:
        status = "No";
        break;
      case CompletionStatus._COMPLETED_MAYBE:
      default:
        status = "Maybe";
        break;
    }

    String message = "CORBA " + corbaName + " " + ex.minor + " " + status;

    // Now map to the correct RemoteException type...
    if (ex instanceof COMM_FAILURE) {
      return new MarshalException(message, ex);
    } else if (ex instanceof INV_OBJREF) {
      RemoteException newEx = new NoSuchObjectException(message);
      newEx.detail = ex;
      return newEx;
    } else if (ex instanceof NO_PERMISSION) {
      return new AccessException(message, ex);
    } else if (ex instanceof MARSHAL) {
      return new MarshalException(message, ex);
    } else if (ex instanceof OBJECT_NOT_EXIST) {
      RemoteException newEx = new NoSuchObjectException(message);
      newEx.detail = ex;
      return newEx;
    } else if (ex instanceof TRANSACTION_REQUIRED) {
      RemoteException newEx = new TransactionRequiredException(message);
      newEx.detail = ex;
      return newEx;
    } else if (ex instanceof TRANSACTION_ROLLEDBACK) {
      RemoteException newEx = new TransactionRolledbackException(message);
      newEx.detail = ex;
      return newEx;
    } else if (ex instanceof INVALID_TRANSACTION) {
      RemoteException newEx = new InvalidTransactionException(message);
      newEx.detail = ex;
      return newEx;
    } else if (ex instanceof BAD_PARAM) {
      Exception inner = ex;

      // Pre-Merlin Sun ORBs used the incorrect minor code for
      // this case.  See Java to IDL ptc-00-01-08 1.4.8.
      if (ex.minor == ORBConstants.LEGACY_SUN_NOT_SERIALIZABLE ||
          ex.minor == OMGSystemException.NOT_SERIALIZABLE) {

        if (ex.getMessage() != null) {
          inner = new NotSerializableException(ex.getMessage());
        } else {
          inner = new NotSerializableException();
        }

        inner.initCause(ex);
      }

      return new MarshalException(message, inner);
    } else if (ex instanceof ACTIVITY_REQUIRED) {
      try {
        Class<?> cl = SharedSecrets.getJavaCorbaAccess().loadClass(
            "javax.activity.ActivityRequiredException");
        Class[] params = new Class[2];
        params[0] = java.lang.String.class;
        params[1] = java.lang.Throwable.class;
        Constructor cr = cl.getConstructor(params);
        Object[] args = new Object[2];
        args[0] = message;
        args[1] = ex;
        return (RemoteException) cr.newInstance(args);
      } catch (Throwable e) {
        utilWrapper.classNotFound(
            e, "javax.activity.ActivityRequiredException");
      }
    } else if (ex instanceof ACTIVITY_COMPLETED) {
      try {
        Class<?> cl = SharedSecrets.getJavaCorbaAccess().loadClass(
            "javax.activity.ActivityCompletedException");
        Class[] params = new Class[2];
        params[0] = java.lang.String.class;
        params[1] = java.lang.Throwable.class;
        Constructor cr = cl.getConstructor(params);
        Object[] args = new Object[2];
        args[0] = message;
        args[1] = ex;
        return (RemoteException) cr.newInstance(args);
      } catch (Throwable e) {
        utilWrapper.classNotFound(
            e, "javax.activity.ActivityCompletedException");
      }
    } else if (ex instanceof INVALID_ACTIVITY) {
      try {
        Class<?> cl = SharedSecrets.getJavaCorbaAccess().loadClass(
            "javax.activity.InvalidActivityException");
        Class[] params = new Class[2];
        params[0] = java.lang.String.class;
        params[1] = java.lang.Throwable.class;
        Constructor cr = cl.getConstructor(params);
        Object[] args = new Object[2];
        args[0] = message;
        args[1] = ex;
        return (RemoteException) cr.newInstance(args);
      } catch (Throwable e) {
        utilWrapper.classNotFound(
            e, "javax.activity.InvalidActivityException");
      }
    }

    // Just map to a generic RemoteException...
    return new RemoteException(message, ex);
  }

  /**
   * Writes any java.lang.Object as a CORBA any.
   *
   * @param out the stream in which to write the any.
   * @param obj the object to write as an any.
   */
  public void writeAny(org.omg.CORBA.portable.OutputStream out,
      java.lang.Object obj) {
    org.omg.CORBA.ORB orb = out.orb();

    // Create Any
    Any any = orb.create_any();

    // Make sure we have a connected object...
    java.lang.Object newObj = Utility.autoConnect(obj, orb, false);

    if (newObj instanceof org.omg.CORBA.Object) {
      any.insert_Object((org.omg.CORBA.Object) newObj);
    } else {
      if (newObj == null) {
        // Handle the null case, including backwards
        // compatibility issues
        any.insert_Value(null, createTypeCodeForNull(orb));
      } else {
        if (newObj instanceof Serializable) {
          // If they're our Any and ORB implementations,
          // we may want to do type code related versioning.
          TypeCode tc = createTypeCode((Serializable) newObj, any, orb);
          if (tc == null) {
            any.insert_Value((Serializable) newObj);
          } else {
            any.insert_Value((Serializable) newObj, tc);
          }
        } else if (newObj instanceof Remote) {
          ORBUtility.throwNotSerializableForCorba(newObj.getClass().getName());
        } else {
          ORBUtility.throwNotSerializableForCorba(newObj.getClass().getName());
        }
      }
    }

    out.write_any(any);
  }

  /**
   * When using our own ORB and Any implementations, we need to get
   * the ORB version and create the type code appropriately.  This is
   * to overcome a bug in which the JDK 1.3.x ORBs used a tk_char
   * rather than a tk_wchar to describe a Java char field.
   *
   * This only works in RMI-IIOP with Util.writeAny since we actually
   * know what ORB and stream we're writing with when we insert
   * the value.
   *
   * Returns null if it wasn't possible to create the TypeCode (means
   * it wasn't our ORB or Any implementation).
   *
   * This does not handle null objs.
   */
  private TypeCode createTypeCode(Serializable obj,
      org.omg.CORBA.Any any,
      org.omg.CORBA.ORB orb) {

    if (any instanceof com.sun.corba.se.impl.corba.AnyImpl &&
        orb instanceof ORB) {

      com.sun.corba.se.impl.corba.AnyImpl anyImpl
          = (com.sun.corba.se.impl.corba.AnyImpl) any;

      ORB ourORB = (ORB) orb;

      return anyImpl.createTypeCodeForClass(obj.getClass(), ourORB);

    } else {
      return null;
    }
  }


  /**
   * This is used to create the TypeCode for a null reference.
   * It also handles backwards compatibility with JDK 1.3.x.
   *
   * This method will not return null.
   */
  private TypeCode createTypeCodeForNull(org.omg.CORBA.ORB orb) {
    if (orb instanceof ORB) {

      ORB ourORB = (ORB) orb;

      // Preserve backwards compatibility with Kestrel and Ladybird
      // by not fully implementing interop issue resolution 3857,
      // and returning a null TypeCode with a tk_value TCKind.
      // If we're not talking to Kestrel or Ladybird, fall through
      // to the abstract interface case (also used for foreign ORBs).
      if (!ORBVersionFactory.getFOREIGN().equals(ourORB.getORBVersion()) &&
          ORBVersionFactory.getNEWER().compareTo(ourORB.getORBVersion()) > 0) {

        return orb.get_primitive_tc(TCKind.tk_value);
      }
    }

    // Use tk_abstract_interface as detailed in the resolution

    // REVISIT: Define this in IDL and get the ID in generated code
    String abstractBaseID = "IDL:omg.org/CORBA/AbstractBase:1.0";

    return orb.create_abstract_interface_tc(abstractBaseID, "");
  }

  /**
   * Reads a java.lang.Object as a CORBA any.
   *
   * @param in the stream from which to read the any.
   * @return the object read from the stream.
   */
  public Object readAny(InputStream in) {
    Any any = in.read_any();
    if (any.type().kind().value() == TCKind._tk_objref) {
      return any.extract_Object();
    } else {
      return any.extract_Value();
    }
  }

  /**
   * Writes a java.lang.Object as a CORBA Object. If <code>obj</code> is an exported RMI-IIOP server
   * object, the tie is found and wired to <code>obj</code>, then written to
   * <code>out.write_Object(org.omg.CORBA.Object)</code>. If <code>obj</code> is a CORBA Object, it
   * is written to <code>out.write_Object(org.omg.CORBA.Object)</code>.
   *
   * @param out the stream in which to write the object.
   * @param obj the object to write.
   */
  public void writeRemoteObject(OutputStream out, java.lang.Object obj) {
    // Make sure we have a connected object, then
    // write it out...

    Object newObj = Utility.autoConnect(obj, out.orb(), false);
    out.write_Object((org.omg.CORBA.Object) newObj);
  }

  /**
   * Writes a java.lang.Object as either a value or a CORBA Object.
   * If <code>obj</code> is a value object or a stub object, it is written to
   * <code>out.write_abstract_interface(java.lang.Object)</code>. If <code>obj</code> is an exported
   * RMI-IIOP server object, the tie is found and wired to <code>obj</code>,
   * then written to <code>out.write_abstract_interface(java.lang.Object)</code>.
   *
   * @param out the stream in which to write the object.
   * @param obj the object to write.
   */
  public void writeAbstractObject(OutputStream out, java.lang.Object obj) {
    // Make sure we have a connected object, then
    // write it out...

    Object newObj = Utility.autoConnect(obj, out.orb(), false);
    ((org.omg.CORBA_2_3.portable.OutputStream) out).write_abstract_interface(newObj);
  }

  /**
   * Registers a target for a tie. Adds the tie to an internal table and calls
   * {@link Tie#setTarget} on the tie object.
   *
   * @param tie the tie to register.
   * @param target the target for the tie.
   */
  public void registerTarget(javax.rmi.CORBA.Tie tie, java.rmi.Remote target) {
    synchronized (exportedServants) {
      // Do we already have this target registered?
      if (lookupTie(target) == null) {
        // No, so register it and set the target...
        exportedServants.put(target, tie);
        tie.setTarget(target);

        // Do we need to instantiate our keep-alive thread?
        if (keepAlive == null) {
          // Yes. Instantiate our keep-alive thread and start
          // it up...
          keepAlive = (KeepAlive) AccessController.doPrivileged(new PrivilegedAction() {
            public java.lang.Object run() {
              return new KeepAlive();
            }
          });
          keepAlive.start();
        }
      }
    }
  }

  /**
   * Removes the associated tie from an internal table and calls {@link Tie#deactivate}
   * to deactivate the object.
   *
   * @param target the object to unexport.
   */
  public void unexportObject(java.rmi.Remote target)
      throws java.rmi.NoSuchObjectException {
    synchronized (exportedServants) {
      Tie cachedTie = lookupTie(target);
      if (cachedTie != null) {
        exportedServants.remove(target);
        Utility.purgeStubForTie(cachedTie);
        Utility.purgeTieAndServant(cachedTie);
        try {
          cleanUpTie(cachedTie);
        } catch (BAD_OPERATION e) {
          // ignore
        } catch (org.omg.CORBA.OBJ_ADAPTER e) {
          // This can happen when the target was never associated with a POA.
          // We can safely ignore this case.
        }

        // Is it time to shut down our keep alive thread?
        if (exportedServants.isEmpty()) {
          keepAlive.quit();
          keepAlive = null;
        }
      } else {
        throw new java.rmi.NoSuchObjectException("Tie not found");
      }
    }
  }

  protected void cleanUpTie(Tie cachedTie)
      throws java.rmi.NoSuchObjectException {
    cachedTie.setTarget(null);
    cachedTie.deactivate();
  }

  /**
   * Returns the tie (if any) for a given target object.
   *
   * @return the tie or null if no tie is registered for the given target.
   */
  public Tie getTie(Remote target) {
    synchronized (exportedServants) {
      return lookupTie(target);
    }
  }

  /**
   * An unsynchronized version of getTie() for internal use.
   */
  private static Tie lookupTie(Remote target) {
    Tie result = (Tie) exportedServants.get(target);
    if (result == null && target instanceof Tie) {
      if (exportedServants.contains(target)) {
        result = (Tie) target;
      }
    }
    return result;
  }

  /**
   * Returns a singleton instance of a class that implements the
   * {@link ValueHandler} interface.
   *
   * @return a class which implements the ValueHandler interface.
   */
  public ValueHandler createValueHandler() {
    return valueHandlerSingleton;
  }

  /**
   * Returns the codebase, if any, for the given class.
   *
   * @param clz the class to get a codebase for.
   * @return a space-separated list of URLs, or null.
   */
  public String getCodebase(java.lang.Class clz) {
    return RMIClassLoader.getClassAnnotation(clz);
  }

  /**
   * Returns a class instance for the specified class.
   *
   * @param className the name of the class.
   * @param remoteCodebase a space-separated list of URLs at which the class might be found. May be
   * null.
   * @param loadingContext a class whose ClassLoader may be used to load the class if all other
   * methods fail.
   * @return the <code>Class</code> object representing the loaded class.
   * @throws ClassNotFoundException if class cannot be loaded.
   */
  public Class loadClass(String className, String remoteCodebase,
      ClassLoader loader) throws ClassNotFoundException {
    return JDKBridge.loadClass(className, remoteCodebase, loader);
  }

  /**
   * The <tt>isLocal</tt> method has the same semantics as the
   * ObjectImpl._is_local method, except that it can throw a RemoteException.
   * (no it doesn't but the spec says it should.)
   *
   * The <tt>_is_local()</tt> method is provided so that stubs may determine
   * if a particular object is implemented by a local servant and hence local
   * invocation APIs may be used.
   *
   * @param stub the stub to test.
   * @return The <tt>_is_local()</tt> method returns true if the servant incarnating the object is
   * located in the same process as the stub and they both share the same ORB instance.  The
   * <tt>_is_local()</tt> method returns false otherwise. The default behavior of
   * <tt>_is_local()</tt> is to return false.
   * @throws RemoteException The Java to IDL specification does to specify the conditions that cause
   * a RemoteException to be thrown.
   */
  public boolean isLocal(javax.rmi.CORBA.Stub stub) throws RemoteException {
    boolean result = false;

    try {
      org.omg.CORBA.portable.Delegate delegate = stub._get_delegate();
      if (delegate instanceof CorbaClientDelegate) {
        // For the Sun ORB
        CorbaClientDelegate cdel = (CorbaClientDelegate) delegate;
        ContactInfoList cil = cdel.getContactInfoList();
        if (cil instanceof CorbaContactInfoList) {
          CorbaContactInfoList ccil = (CorbaContactInfoList) cil;
          LocalClientRequestDispatcher lcs = ccil.getLocalClientRequestDispatcher();
          result = lcs.useLocalInvocation(null);
        }
      } else {
        // For a non-Sun ORB
        result = delegate.is_local(stub);
      }
    } catch (SystemException e) {
      throw javax.rmi.CORBA.Util.mapSystemException(e);
    }

    return result;
  }

  /**
   * Wraps an exception thrown by an implementation
   * method.  It returns the corresponding client-side exception.
   *
   * @param orig the exception to wrap.
   * @return the wrapped exception.
   */
  public RemoteException wrapException(Throwable orig) {
    if (orig instanceof SystemException) {
      return mapSystemException((SystemException) orig);
    }

    if (orig instanceof Error) {
      return new ServerError("Error occurred in server thread", (Error) orig);
    } else if (orig instanceof RemoteException) {
      return new ServerException("RemoteException occurred in server thread",
          (Exception) orig);
    } else if (orig instanceof RuntimeException) {
      throw (RuntimeException) orig;
    }

    if (orig instanceof Exception) {
      return new UnexpectedException(orig.toString(), (Exception) orig);
    } else {
      return new UnexpectedException(orig.toString());
    }
  }

  /**
   * Copies or connects an array of objects. Used by local stubs
   * to copy any number of actual parameters, preserving sharing
   * across parameters as necessary to support RMI semantics.
   *
   * @param obj the objects to copy or connect.
   * @param orb the ORB.
   * @return the copied or connected objects.
   * @throws RemoteException if any object could not be copied or connected.
   */
  public Object[] copyObjects(Object[] obj, org.omg.CORBA.ORB orb)
      throws RemoteException {
    if (obj == null)
    // Bug fix for 5018613: JCK test expects copyObjects to throw
    // NPE when obj==null.  This is actually not in the spec, since
    // obj is not really an RMI-IDL data type, but we follow our
    // test here, and force this error to be thrown.
    {
      throw new NullPointerException();
    }

    Class compType = obj.getClass().getComponentType();
    if (Remote.class.isAssignableFrom(compType) && !compType.isInterface()) {
      // obj is an array of remote impl types.  This
      // causes problems with stream copier, so we copy
      // it over to an array of Remotes instead.
      Remote[] result = new Remote[obj.length];
      System.arraycopy((Object) obj, 0, (Object) result, 0, obj.length);
      return (Object[]) copyObject(result, orb);
    } else {
      return (Object[]) copyObject(obj, orb);
    }
  }

  /**
   * Copies or connects an object. Used by local stubs to copy
   * an actual parameter, result object, or exception.
   *
   * @param obj the object to copy.
   * @param orb the ORB.
   * @return the copy or connected object.
   * @throws RemoteException if the object could not be copied or connected.
   */
  public Object copyObject(Object obj, org.omg.CORBA.ORB orb)
      throws RemoteException {
    if (orb instanceof ORB) {
      ORB lorb = (ORB) orb;

      try {
        try {
          // This gets the copier for the current invocation, which was
          // previously set by preinvoke.
          return lorb.peekInvocationInfo().getCopierFactory().make().copy(obj);
        } catch (java.util.EmptyStackException exc) {
          // copyObject was invoked outside of an invocation, probably by
          // a test.  Get the default copier from the ORB.
          // XXX should we just make the default copier available directly
          // and avoid constructing one on each call?
          CopierManager cm = lorb.getCopierManager();
          ObjectCopier copier = cm.getDefaultObjectCopierFactory().make();
          return copier.copy(obj);
        }
      } catch (ReflectiveCopyException exc) {
        RemoteException rexc = new RemoteException();
        rexc.initCause(exc);
        throw rexc;
      }
    } else {
      org.omg.CORBA_2_3.portable.OutputStream out =
          (org.omg.CORBA_2_3.portable.OutputStream) orb.create_output_stream();
      out.write_value((Serializable) obj);
      org.omg.CORBA_2_3.portable.InputStream in =
          (org.omg.CORBA_2_3.portable.InputStream) out.create_input_stream();
      return in.read_value();
    }
  }
}

class KeepAlive extends Thread {

  boolean quit = false;

  public KeepAlive() {
    setDaemon(false);
  }

  public synchronized void run() {
    while (!quit) {
      try {
        wait();
      } catch (InterruptedException e) {
      }
    }
  }

  public synchronized void quit() {
    quit = true;
    notifyAll();
  }
}
